The 802.11 protocol suite specified by the Institute of Electrical and Electronics Engineers (Institute of Electrical and Electronics Engineers, IEEE) is a standard for a wireless local area network (Wireless local Access Network, WLAN), and existing WLAN standards based on the orthogonal frequency division multiplexing (Orthogonal Frequency Division Multiplexing, OFDM) technology include evolving standards such as 802.11a, 802.11n, and 802.11ac, and are still continuously evolving. With the development and gradual popularization of the WLAN, a case in which WLAN apparatuses supporting different standards coexist will exist in a long term. To implement backward compatibility, an access point (Access Point, AP) and a station (Station, STA) with a new-generation standard need to support earlier standards.
Frame formats used by multiple existing WLAN standards and future WLAN standards are different. Therefore, a WLAN apparatus employing a new-generation standard needs to have a capability of recognizing a frame of a particular WLAN standard, and the frame of the particular WLAN standard does not affect receiving of a frame of another standard.